1. Field
Example embodiments relate to methods of patterning holes spaced apart from each other in a graphene layer and/or methods of fabricating a transparent electrode by using the patterned graphene layer and adjusting a scanning speed and a repetition rate of a pulse laser.
2. Description of the Related Art
Display devices and other various devices (e.g., solar cells) need a transparent electrode, which is generally made of indium tin oxide (ITO). However, as use of indium increases, the price thereof rises as resources are depleted. Also, an ITO electrode has insufficient ductility, and thus, cracks are generated when the ITO electrode is bent. Accordingly, the resistance of the ITO electrode should be increased. Therefore, there is a need for an electrode material that may substitute ITO and studies on graphene as an alternative material have been performed.
The transmittance of graphene in a visible region is important in order to use graphene to manufacture a transparent electrode of various display devices. Because graphene is a material that reduces the transmittance of a transparent electrode by about 2.3% per mono-layer, a method of forming hole patterns by making many holes in a line in the graphene has been used to increase the light transmittance of graphene and obtain an effective transmittance suitable for a transparent electrode of a display device. A photo process using a photosensitive photoresist, which is a semiconductor process, and a reactive ion etching (RIE) method of applying an oxygen plasma have been used for patterning graphene holes.
However, with regard to the photo process using the photosensitive photoresist, the graphene transferred onto a transparent polymer substrate may be torn due to weak adhesiveness between the transparent polymer substrate and a graphene material during a photoresist removing process. Additionally, a contact resistance of the graphene may increase, and thus, perfectly removing the photoresist from graphene may be difficult. Furthermore, when the RIE method is used and oxygen plasma is applied for etching, the transparent polymer substrate may be damaged as not only graphene but also the transparent polymer substrate is etched.